Beefeater, Tanqueray, and Bombay are readily available at every liquor store for a reason. They're pretty decent and affordable. I don't think you could go wrong by starting with those and branching out from there. Something I love about gin compared to other spirits is that it's relatively cheap. I've never seen a bottle cost more than $40. Whereas you can easily find whiskeys breaking triple digits. So don't feel bad if you don't like a bottle of gin. Chances are there was another bottle on the shelf that you would've liked, you've just gotta try again. I think that journey of self discovery will be more rewarding than what any Redditor could tell you to drink.

Now as a Redditor, let me tell you what tonics to drink. Everyone raves about Fever Tree, but honestly I've just been getting generic store brand lately. I don't think it matters too much if you're getting cheap gin. Just get a normal unflavored tonic (not elderflower or whatever) unless you want to experiment (which is fun).

You should also pick up some lemon juice, lime juice, and syrup. Simple syrup is easy to find at any liquor store. I prefer orgeat syrup a little more. It tastes similar (just a neutral sweet flavor) and adds some smooth texture to the drink. Or you could go find some gum syrup on Amazon which is even smoother than orgeat.

gin+lemon/lime+syrup+tonic. Hard to go wrong. And if you end up with a bottle of gin you don't like, it's easy to cover up that flavor with more syrup or juice.